US PGA Championship winner Jason Dufner is hoping to be back firing on all cylinders at this week's $2.5 million Qatar Masters after being laid low by bronchitis and pneumonia.

The 36-year-old American did well to finish nine strokes adrift of winner Jimmy Walker after becoming ill at the Sony Open in Hawaii two weeks ago.

"I got bronchitis and pneumonia when I was at the Sony so I've been trying to deal with that and trying to get healthier," he told the European Tour website (www.europeantour.com) on Tuesday.

"I didn't do much practising at home last week, I was trying to get healthy."

This week represents a rare European Tour foray for Dufner who is looking to improve on the tie for ninth he achieved at the Doha Golf Club 12 months ago.

"We've got a great field again this year," said the world number 13. "It's a long golf course, a lot of the par-fives are not reachable for me so I need to be in the fairway.

"I need to wedge it well on the par-fives, the rough is up a good bit this year," added Dufner who landed his first major when he won the US PGA at Oak Hill in August.

The title favourite in Qatar is world number three Henrik Stenson who will aim to rebound after missing the cut in last week's Abu Dhabi Championship, the first event of the tour's 'Desert Swing' which ends with next week's Dubai Classic.

"I feel my game is heading in the right direction," said the Swede. "Last week was not quite what I wanted but I had limited preparations and it now feels like I'm starting to hit the ball a bit better."

Stenson has a good record at the Doha Golf Club, having won in 2006 and three times been a runner-up at the venue.

"I think I'm in a position in the world rankings that if I keep playing well I will have a chance to first overtake Adam (Scott) and then maybe challenge Tiger (Woods) for the number one spot," he said.

"It would be a nice thing to have on the CV when I put the clubs in the closet one day, that I've held the number one spot at some time."

Former world number ones Ernie Els and Luke Donald, Spaniard Sergio Garcia and American John Daly are also among the lineup in Qatar.